1/*
2   base64.cpp and base64.h
3
4   Copyright (C) 2004-2008 Ren� Nyffenegger
5
6   This source code is provided 'as-is', without any express or implied
7   warranty. In no event will the author be held liable for any damages
8   arising from the use of this software.
9
10   Permission is granted to anyone to use this software for any purpose,
11   including commercial applications, and to alter it and redistribute it
12   freely, subject to the following restrictions:
13
14   1. The origin of this source code must not be misrepresented; you must not
15      claim that you wrote the original source code. If you use this source code
16      in a product, an acknowledgment in the product documentation would be
17      appreciated but is not required.
18
19   2. Altered source versions must be plainly marked as such, and must not be
20      misrepresented as being the original source code.
21
22   3. This notice may not be removed or altered from any source distribution.
23
24   Ren� Nyffenegger rene.nyffenegger@adp-gmbh.ch
25
26*/
27
28#include "base64.h"
29#include <iostream>
30
31static const std::string base64_chars =
32             "ABCDEFGHIJKLMNOPQRSTUVWXYZ"
33             "abcdefghijklmnopqrstuvwxyz"
34             "0123456789+/";
35
36
37static inline bool is_base64(unsigned char c) {
38  return (isalnum(c) || (c == '+') || (c == '/'));
39}
40
41std::string base64_encode(unsigned char const* bytes_to_encode, unsigned int in_len) {
42  std::string ret;
43  int i = 0;
44  int j = 0;
45  unsigned char char_array_3[3];
46  unsigned char char_array_4[4];
47
48  while (in_len--) {
49    char_array_3[i++] = *(bytes_to_encode++);
50    if (i == 3) {
51      char_array_4[0] = (char_array_3[0] & 0xfc) >> 2;
52      char_array_4[1] = ((char_array_3[0] & 0x03) << 4) + ((char_array_3[1] & 0xf0) >> 4);
53      char_array_4[2] = ((char_array_3[1] & 0x0f) << 2) + ((char_array_3[2] & 0xc0) >> 6);
54      char_array_4[3] = char_array_3[2] & 0x3f;
55
56      for(i = 0; (i <4) ; i++)
57        ret += base64_chars[char_array_4[i]];
58      i = 0;
59    }
60  }
61
62  if (i)
63  {
64    for(j = i; j < 3; j++)
65      char_array_3[j] = '\0';
66
67    char_array_4[0] = (char_array_3[0] & 0xfc) >> 2;
68    char_array_4[1] = ((char_array_3[0] & 0x03) << 4) + ((char_array_3[1] & 0xf0) >> 4);
69    char_array_4[2] = ((char_array_3[1] & 0x0f) << 2) + ((char_array_3[2] & 0xc0) >> 6);
70    char_array_4[3] = char_array_3[2] & 0x3f;
71
72    for (j = 0; (j < i + 1); j++)
73      ret += base64_chars[char_array_4[j]];
74
75    while((i++ < 3))
76      ret += '=';
77
78  }
79
80  return ret;
81
82}
83
84std::string base64_decode(std::string const& encoded_string) {
85  int in_len = encoded_string.size();
86  int i = 0;
87  int j = 0;
88  int in_ = 0;
89  unsigned char char_array_4[4], char_array_3[3];
90  std::string ret;
91
92  while (in_len-- && ( encoded_string[in_] != '=') && is_base64(encoded_string[in_])) {
93    char_array_4[i++] = encoded_string[in_]; in_++;
94    if (i ==4) {
95      for (i = 0; i <4; i++)
96        char_array_4[i] = base64_chars.find(char_array_4[i]);
97
98      char_array_3[0] = (char_array_4[0] << 2) + ((char_array_4[1] & 0x30) >> 4);
99      char_array_3[1] = ((char_array_4[1] & 0xf) << 4) + ((char_array_4[2] & 0x3c) >> 2);
100      char_array_3[2] = ((char_array_4[2] & 0x3) << 6) + char_array_4[3];
101
102      for (i = 0; (i < 3); i++)
103        ret += char_array_3[i];
104      i = 0;
105    }
106  }
107
108  if (i) {
109    for (j = i; j <4; j++)
110      char_array_4[j] = 0;
111
112    for (j = 0; j <4; j++)
113      char_array_4[j] = base64_chars.find(char_array_4[j]);
114
115    char_array_3[0] = (char_array_4[0] << 2) + ((char_array_4[1] & 0x30) >> 4);
116    char_array_3[1] = ((char_array_4[1] & 0xf) << 4) + ((char_array_4[2] & 0x3c) >> 2);
117    char_array_3[2] = ((char_array_4[2] & 0x3) << 6) + char_array_4[3];
118
119    for (j = 0; (j < i - 1); j++) ret += char_array_3[j];
120  }
121
122  return ret;
123}